Conference Coverage

Expanded hospital testing improves respiratory pathogen detection



– Systematic testing of acute respiratory illness patients can increase the likelihood of finding relevant pathogens, according to a study presented at an annual scientific meeting on infectious diseases.

Currently, hospitals conduct either nonroutine assessments or rely heavily on clinical laboratory testing among severe acute respiratory illness patients, which can lead to missing clinically key viruses.

This negative-stained transmission electron micrograph depicts the ultrastructural details of an influenza virus particle or “virion.” Cynthia Goldsmith/CDC photo #10073
“Detections of some potentially relevant viruses, such as air influenza viruses and human metapneumovirus were often not detected in hospital testing,” said presenter Andrea Steffens, MPH, epidemiologist at the Centers for Disease Control and Prevention.

Systematic testing expands on tests ordered and carried out at hospitals, expanding on them by testing for influenza, respiratory syncytial virus (RSV), human metapneumovirus, rhinovirus and enterovirus, adenovirus, coronavirus, and parainfluenza viruses 1-4. To test the efficacy of systematic testing, investigators studied 2,216 severe acute respiratory illness patients hospitalized in one of three hospitals in Minnesota during September 2015-August 2016. Patients were predominantly younger than 5 years old (57%) and had one or more chronic medical condition (63%).

Detection of at least one virus increased from 1,062 patients (48%) to 1,600 patients (72%) when comparing clinically ordered tests against expanded, systematic RT-PCR testing conducted through the Minnesota Health Department (MDH).

By patient age, viral detection increased by 27%, 24%, 18%, and 21% for patients aged younger than 5 years, 5-17 years, 18-64 years, and 65 years and older, respectively. Except for influenza viruses and RSV, the proportions of viruses identified, regardless of age, were all lower in hospital testing, compared with MDH testing.

“RSV targeting was almost systematic among children less than 5 years, but [accounted for] only 28% of RSV detection,” said Dr. Steffen in her presentation. “A smaller proportion of other respiratory viruses, including the human metapneumovirus, were detected at the hospital, and this was especially true for adults.”

Patients with rhinovirus and enterovirus saw a difference between hospital and expanded testing, increasing from a little over 300 patients detected, to nearly 800 patients.

“Patients admitted to the ICU were less likely to have a pathogen detection than those not admitted to the ICU, and those with one or more chronic medical condition had lower viral detection than those without,” Dr. Steffens said. “While testing at MDH did increase the percent of patients in each category, trends remained consistent and significant.”

Since testing information was only collected for patients with positive test results at the hospital, investigators were not able to compare testing practices between patients with and without viruses. This study may also have underrepresented pathogens detected through means other than the hospital laboratory, like rapid tests in emergency departments. The study was also limited by the short time frame of only 1 year.

The presenters reported no relevant financial disclosures.

SOURCE: Steffens A et al. Abstract 885.

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